Double-walled metal combustion chamber



Sept. 18, 1956 P. SCHUSTER 2,763,321

DOUBLE-WALLED METAL COMBUSTION CHAMBER Filed Aug. 26, 1949 $10M 2 6-3 131C145 IU6 United States Patent DOUBLE-WALLED METAL COMBUSTION CHAMBER Paul Schuster, Jenkintown, Pa., assignor to Custom Metal Products, Inc., Philadelphia, Pa., a corporation of Pennsylvania Application August 26, 1949, Serial No. 112,460

10 Claims. (Cl. 158-1) The invention relates to improvements in double-walled metal combustion chambers, and more specifically to improvements in chambers comprising removably interconnected double-walled sectors of the type disclosed in the copending patent application Serial No. 89,254 of applicant and Murrell F. Dobbins, In, filed April 23, 1949, for Metal Combustion Chamber and Furnace With Such Chamber."

The main objects of the invention are to increase the stiffness of double-Walled metal combustion chambers without increase but rather with a decrease in the gauge of the sheet metal of which the chamber is made, and to maintain the desired shape of the chamber during shipment, installation and under the influence of the combustion temperatures.

The invention achieves these objects by bracing the inner wall by spacers against the outer wall distributed over the extent of these walls at such locations as to prevent the inner wall from arching outwardly when heated to the high combustion temperatures and, in the case. of a sectional combustion chamber, by providing joints between the diiferent sectors which restrict relative circumferential movement of the adjoining margins of the inner walls relative to each other.

The objects, advantages and features of the invention are more fully explained and will be more easily understood from the following description of several embodiments of the invention which are illustrated in the attached drawing.

In the drawing;

Figure 1 is a small-scale side elevation of a combusti n chamber and a fragmentary section of adjoining parts of a furnace in which it is installed, and of adjoining portions of a gun-type fuel burner;

Figure 2 is a fragmentary plan view and section along line 22 of Figure 1 on a larger scale;

Figures 3 and 4 are vertical local, somewhat diagrammatic sections along lines 33 and 44, respectively, of Figure 2 on a somewhat smaller scale;

Figure 5 is a fragmentary perspective view of part f. a spacer between inner and outer walls;

Figure 6 is a section corresponding to Figure 4 of a modified, construction of the chamber in the region of the entrance opening for the burner barrel; and

Figure 7 is a section corresponding to part of Figure 2 illustrating a modified form of the connection between adjoining wall sections, sectors or units.

Figure 1 shows a generally prismatic or tubular combustion chamber 16 supported on floor 11 in the interior of furnace 12. Barrel 13 of a gun-type oil burner registers with an opening in chamber 10. The space between chamber and the furnace walls is filled with loose insulating material 14 topped with refractory cement or other solid material 15.

Chamber 10, as shown in Figures 2 to 5, is composed of a number of identical sectors 16, a sector 17 provided with a slide 18, and a pair of bottom units 19. Each of the sectors 16 and 17 has inner and outer walls 20, 21

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and 22, 23 respectively. The outer walls 21 and 23 have narrow outwardly directed flanges 24 along their side margins, and these flanges are connected, such as by spot welding, to flanges 25, 26 of the inner walls 20 and 2.2. Flange 26 has a reversely bent outer extension 27 which receives the connected flanges 24, 25 of the adjoining sector. The construction described so far is disclosed in the earlier above-cited application.

The inner portion of flange 26 is reversely bent upon the respective margin of inner wall 20 or 22 at 28 and the region where wall 20 (or 22) and flange 26 meet is radially and outwardly angled 011 or flanged at 29. Flange 29 presents a radially outwardly extending ridge and presents with portion 28 and flange 26 an outwardly facing channel. The connecting region between flange 25 and the adjoining margin of inner wall 20 (or 22) is formed as a radially inwardly facing, channel 30 and a radially inwardly projecting ridge 31 adapted, respectively, for interlocking engagement with flange 26. and projection 29;

Ventilatedspacers 32 are inserted between the inner and outer walls 20, 21 of the unit 16. These spacers, in the embodiment illustrated in Figures 1 to 5, are circumferentially arrangedsections, located near the top and bottom margins and about midway between these margins. The number of spacers employed depends on the size of the chamber, the properties and dimensions of the material used for the chamber walls, and on the temperatures to be sustained. In certain" cases, a spacer near topand bottom or a singlespacer, e. g., in the mid region, will suifi'ce, whereas in other cases a greater number of spacers should be-provided.

Spacer 32 consists of a sheet metal strip having a web 33, an inner flange or arm 34 andouter arms 35'. The illustrated Z-section form is preferred. Outer arms 35 and at least a large adjoining part of the width of web 33 are subdivided by a plurality of recesses or-notches 36. These notches 36 not only permit easy bending of the spacer strip 32 so as to snugly fit against the outer and inner walls, but" they also provide for the desired ventilation of the space between the walls so that heat may radiate from this space into the interior of the furnace.

The strips 32 are secured, such as by spot welds 37, through their arms 35 to the outer wall 21 only, whereas flange 34 merely rests against the outer surface of inner wall 20. Not only here but throughout, connecting means, such as spot welds or the like, are avoided on the inside of the chamber which is subject to the high combustion temperatures.

A spacer 32, see Figures 2 and 4, isalso provided along one of theend margins, here the lower margin of unit 17. The provision of but one ventilated spacer 32 permits removal, insertion and exchange of slide'18 which serves for the adjustable accommodation of'burner barrel 13'. So as to obtain thedesired'bracing'effect between outer and inner walls 22, 23 of unit 17, slide 18 has ventilated spacer strips 38 inserted between its inner wall 39' and outer wall 40' near the top and bottom margins thereof; The spacer strips 38 may be ofsubstantially identical construction, arrangement and attachment as illustrated and described for the strips 32.

When the new combustion chamber is heated. to. the high temperatures of the burner flame, the inner walls; of its sectors are prevented from bending or bulging outwardly between their margins due to thermal expansion and to open up the joints between them. The outward bulgin'g is resisted by the ventilated spacer strips 32 and 38, and the opening of the joints is prevented by the-interlock on the inside provided by the elements 26, 28; 29 and'25, 30, 31.

In: some cases, combustion" chambers. Willi be mass produced for one specific type of burner and furnace. In

such a case, economies can be achieved by dispensing with slide 18 and merely providing, as shown in Figure 6, walls 41 and 42 of sector 43 with registering openings 44 of predetermined size and location. In this event, a ventilated spacer 45 is advantageously located between the walls just above and below said opening.

Economies may also be achieved by providing a twoor more piece bottom 19 of ceramic material, as indicated in the drawing, instead of a bottom made of expensive high-temperature-resisting sheet metal, as per the cited copending application.

Figure 7 shows a modification of the joint between adjoining sectors. In this case, inner wall 46 ends along one side margin in a narrow outwardly directed flange 47 and along the opposite margin of the adjoining unit in an angle-section flange having arms 48 and 49. Flange 47 is connected by spot welds to a marginal outwardly directed flange 50 of angle-section member 51 which by its other arm is secured to flange 52 of outer wall 53, this arm ending in the outer connecting channel 54.

Flange or arm 49 is outwardly offset from inner wall 46 and overlappingly secured to the web 55 of a generally Z-section strip, the one arm 56 of which extends radially inwardly at a distance from arm 48 of the outer wall so as to provide a channel for the reception of flanges 47, 50 of the adjoining outer wall. The other arm 57 of the Z-section strip is overlappingly secured to marginal flange 52 of outer wall 53 and is received together with the latter in the outer channel 54 along the side margin of the adjoining sector. Also in this case, spot welds or similar connecting means are located outside of the inner surface of the chamber, which is exposed to the flame and the combustion products.

The installation of the new chamber in a furnace or its removal therefrom is the same as described in the above-cited copending prior application. First the bottom unit parts 19 are assembled in the interior of furnace 12 on floor 11; then all but one of the sectors 16, 17 have their margins hooked or slid into each other after their introduction into furnace 12; and finally the last sector 16 or 17 is slid into place and the entire prismatic or tubular portion formed by the sectors is placed over the bottom 19. It now remains merely to install the burner, to fill in the loose insulation material 14 between furnace wall and chamber and, if desired, to cap the insulation material with refractory cement or other material.

The invention is not restricted to the illustrated and described embodiments but is susceptible to modifications and to adaptations. For instance, other means than those specifically disclosed may be used for bracing the inner wall against the outer wall, and other forms of connecting means permitting easy assembly of the sectors while holding them on inside and outside against relative movement in circumferential direction will occur to those skilled in the art without departing from the spirit of the invention.

What is claimed is:

l. A combustion chamber for furnaces, the chamber having a body of generally prismatic shape and composed of a plurality of sectors each having an outer wall and a radially spaced inner wall, said walls of each sector being permanently interconnected and provided along their margins paralleling the axis of the prismatic shape with means for removably connecting the sectors with each other at their outer as Well as at their inner walls for interlockingly holding adjoining sectors against relative movement except in the direction of the axis of the prismatic shape.

2. A combustion chamber for domestic furnaces with gun-type fluid-fuel burner, the chamber being of generally prismatic shape and composed of a plurality of sectors each having an outer wall and a radially spaced inner wall, said walls of each sector being permanently intercon ected and provided along their margins paralleling the axis of the prismatic shape with means for removably connecting the sectors with each other, and spacers attached to said outer walls between said margins and extending toward said inner Walls so as to restrain the latter from undue outward buckling when subjected to the heat of a burner flame.

3. Spacer adapted for insertion between an imperforate inner wall and an outer wall of a double-walled combustion chamber for furnaces, in the form of a metal section having a web and an arm along at least one margin of and extending transversely to said web, said arm and at least the adjoining part of said web being subdivided by transverse slots so as to facilitate bending of the spacer to the configuration of said walls and to provide ventilating openings, said arm providing attachment means adapted for securing the spacer to one of the chamber walls.

4. Spacer between an imperforate inner wall and an outer wall of a double-walled combustion chamber for furnaces, in the form of a metal section having a web and arms along both margins of and extending transversely to said web, one of said arms and at least the adjoining part of said web being subdivided by transverse slots so as to facilitate bending of the spacer to the configuration of said walls and to provide ventilating openings, said arms serving as abutments for the chamber walls.

5. Double-walled, generally prismatic combustion chamber for furnaces composed of a plurality of removably connected sectors, said sectors being provided along their meeting margins at the inside as well as on the outside with circumferentially interlocking connecting means, said interlocking means at the inside being arranged outside of and covered by the inner walls of said sectors.

6. Double-walled, generally prismatic combustion chamber for furnaces composed of a plurality of doublewalled sectors, one of two adjoining sectors being provided along the side margin of its inner wall with a radially outwardly projecing ridge adjoined by a radially outwardly facing channel, and the other sector being provided along the side margin of its inner wall with an inwardly projecting ridge adjoined by an inwardly open channel, said ridges and channels of the adjoining sectors engaging each other so as to permit relative movement of the sectors in the direction of their side margins while locking the sectors against movement in circumferential direction.

7. Combustion chamber according to claim 6, in which said ridges and channels are formed as integral one-piece portions of the inner walls of said sectors.

8. Combustion chamber according to claim 7 in which said inner walls are provided along their side margins with radially outwardly directed flanges to which separately manufactured parts are permanently secured, said flanges and parts forming together said ridges and channels, and said parts forming permanent connecting means between the inner and outer walls of the individual sectors.

9. A double-walled furnace combustion chamber having registering openings formed in the inner and outer walls thereof, a double-walled slide between said walls formed with smaller registering openings in its inner and outer walls for accommodating the barrel of a fuel burner, and ventilated spacers between said last-named Walls for holding them as well as the first-named walls at the desired distance from each other.

10. A combustion chamber according to claim 9, provided with additional spacing means between the inner and outer walls of the chamber along at least one of its circumferential margins.

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